fixed #14084 - run CMake with `--warn-uninitialized` in CI #502

Job	Run time
iwyu (macos-26, libc++, -Xiwyu --mapping_file=$(realpath ./macos.imp))	7m 47s
iwyu (ubuntu-22.04, fedora:latest, libstdc++, -isystem/usr/lib/clang/20/include)	6m 39s
clang-include-cleaner (libstdc++)	9m 13s
clang-include-cleaner (libc++)	10m 22s
	34m 1s

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